Boat



1961 s. MILLS 2,995,104

BOAT

Filed Dec. 7, 1959 2 Sheets-Sheet 1 lA/V'A/TOR.

al/ONE) MILLS A 7' TOR/YE Y8.

Aug. 8, 1961 s. MILLS 2,995,104

BOAT

Filed Dec. 7, 1959 2 Sheets$heet 2 IIVVEIVTOR. SIDNEY M/LLJ' ATTORNEYS.

United tates This invention relates to a boat.

An object of this invention is to provide a boat construction whichpasses through its surrounding fluids with a of drag, and thereby canmake its way at various speeds with less power than other boats ofsimilar weight at the same speeds. A related object is to provide such aboat which is stable and will give a smooth ride.

Still another object is to provide a boat structure in which thepassengers may be completely enclosed if desired, and which provides asubstantially maximum area of deck space per unit of width.

Still a further object of the invention is to provide a rudderless boatwherein directional control may be exerted by propulsion means, whichmeans may be so disposed as to operate at their optimum conditions.

A feature of the invention resides in providing a hull having a bottomand an upper decking, both of which are formed as surfaces of revolutiongenerated by an elliptical arc revolved around the vertical central axisof the boat. The resulting hull structure is substantially circular inplan view, and is substantially eliptical along any elevation. It hasbeen found that this shape results in a construction wherein theresistance to surrounding fluids, both the water in which it floats, andthe air above the water, is held to a substantial An additional featureof the invention resides in the provision of a plurality of sponsonsprojecting beneath the boat, there preferably (although not necessarily)being three of said sponsons: a central keel sponson, and a port andstarboard sponson, one on each side of the keel sponson. These sponsonsprovide two channels between which preferably, but not necessarily, areso shaped as to form a venturi structure that tends to lift the boat outof the Water when it is under way. Propulsion means are placed in atleast two of said channels, whereby the boat may be steered bydifferential operation thereof.

According to still another preferred but optional feature of theinvention, a canopy may be placed atop the decking which itself ispreferably a surface of revolution generated by an elliptical arcrevolved around the vertical central axis, said canopy being solid andirnperforate, if desired, and ventilating means such as a snorkelventilator or the like, ventilating the canopy, thereby keeping theinterior of the boat dry, even in rough weather.

The above and other features of this invention will be fully understoodfrom the following detailed description and the accompanying drawings,in which:

FIG. 1 is a plan view of a boat according to the invention;

FIG. 2 is a side elevation taken at line 22 of FIG. 1;

FIG. 3 is a bottom view of the boat shown in FIG. 1;

FIG. 4 is a head-on view taken at line 44 of FIG. 1;

FIG. 5 is a cross-section taken at line 55 of FIG. 3;

FIG. 6 is a fragmentary cross-section taken at line 6-6 of FIG. 3; and

FIG. 7 is a cross-section of a detail of the boat shown in FIG. 1.

FIG. 1 shows a boat 10 according to the invention. The boat issubstantially circular in plan view as shown, the hull 11 having itsoutermost limits defined by a joint 12. A fantail 13 is integral withthe hull and modifies its circuar shape at the rear thereof. Forwardaxis 14 indicates the forward direction of the boat for purposes ofreference.

Patented Aug. 8, 1961 The fantail has sides 15, 16 which are preferablystraight lines tangent to joint 12, and which form an acute anglebetween them. The acute angle opens toward the boat. The stern end 17 ofthe fantail is preferably a straight edge extending parallel to thetransverse axis 18 of the boat. The transverse axis is normal to thevertical axis 30 and forward axis 14.

The hull includes a decking 19 having an opening 20 therein. Thisopening may be left open if no protection from the elements is desiredfor the passengers, but usually a canopy 21 is provided. The canopy is acomplete enclosure. It is provided with a door 22 for entry. A snorkeltube 23 is placed atop the canopy for ventilation purposes. It serves toventilate the region beneath the canopy.

The interior of the hull is provided with a flooring 24 on which restseats 25. Controls 26 are provided for maneuvering the craft.

Reference should now be made to FIGS. 2 and 4 for a full disclosure ofthe geometrical configuration of the outer surfaces of the boat.

As can best be seen in FIG. 2, the hull includes a bottom 27 which isjoined by attach means 28 to decking 19. The decking 19 has the canopyattached to it by attach means 29. The outer surfaces of the bottom, thedecking and the canopy are surfaces of revolution formed by arcs ofellipses rotated around the vertical axis 30 of the boat. The verticalaxis of the boat is substantially normal to the water when the boatrests in the water, and is shown in FIG. 4. Arcs 31, 32, and 33 whichgenerate the canopy surface, decking surface, and bottom surface areindicated by brackets in FIG. 4.

Preferably, but not necessarily, arcs 32 and 33 which generate thebottom and the decking surfaces, are from the same ellipse, althoughthey may be from different ellipses if desired. The canopy may have aslightly greater minor axis in order to give greater head room for theoccupants of the boat than if are 32 were continued to make a completeellipse. It is to be understood that it is within the scope of thisinvention, however, to make the cross-section through the central axis acomplete ellipse by completing the ellipse which would be generated byarcs 32 and 33. The major axes of all the elliptical arcs lie in planesparallel to the plane in which joint 12 lies.

In FIG. 7, there are shown attach means 28 which are utilized to joindecking 19 and bottom 27. A hookshaped flange 34 is formed around thelower edge of decking 19, and a similar hook-shaped flange 35 is formedaround the edge of bottom 27. The hooks are oppositely directed. Thereare flat surfaces 34a and 34b just inside the hooks. A layer of cement34c joins the bottom and decking by cementing them together. An epoxyresin formulation is. a suitable cement. A collision bumper 36 of someresilient material such as silicone rubber, may be snapped over thehooks around the edge of the boat.

The construction of this hull renders its susceptible to being made morebuoyant by the inclusion therein of a foam-in-place plastic material.The craft may thereby be made substantially urlsinkable. As is shown inFIGS. 5-7, a buoyant, non-porous material such as urethane foam may becast or otherwise inserted inside the hull at the outer joint of thedecking and bottom, around the complete periphery thereof. It serves notonly to increase buoyancy, but also acts as an additional means forattaching the two hull portions together. Furthermore, this material maybe cast into the unused bottom sections beneath the flooring foradditional buoyancy.

FIG. 6 illustrates a means for attaching the canopy to the decking. AU-shaped head 38 is pressed over an upright flange 39 on the decking,and the canopy is pressed over the outside of the U-shaped bead, wherethe resilience of the bead presses back against the canopy to hold iton. The canopy can be removed when desired by snapping it ofl? of thebead. Screws, hold-down lugs, or the like, may also be provided to holddown the canopy to the decking, either permanently or semi-permanently.

While the hull is described herein as being formed of continuous arcs ofthe shapes defined, it will be understood that the fantail and certainelements yet to be described are appended thereto, and while theyinterrupt the continuity of the arcs, it may be imagined that the hullis a continuous surface beneath them. The protuberances are merely localmodifications of a generally and substantially continuously curvedstructure.

The hull has attached to its bottom and protruding downward therefrom acentral keel sponson 46 (FIG. 4) and a port and a starboard sponson 41,42. The keel sponson is on the center line of the boat and extends in aforward direction. Sponsons 41 and 42 are generally aligned with thekeel sponson. They are spaced from it, one on each side, and formchannels 43, 44 therebetween.

The keel sponson has a heel 45 which is a flat area spaced to the rearof the central axis of the boat. A curved surface 46, generated by astraight-line generator maintained parallel to transverse axis 18extends forwardly from the keel and merges with the bottom about at thecentral axis of the boat. On each side of surface 46 there are curvedsides 47, 48 which converge toward the front end of the keel sponson,diverge toward its middle, and again converge toward the rear face 49thereof. The rear face of the sponson is a sloping planar rear surfacewhich intersects the heel, the two sides 47, 48, and the bottom surfaceof the fantail. Surfaces 47 and 48 intersect surface 46, the bottom ofthe boat, and the bottom of the fantail.

The port and starboard sponsons are mirror images of each other, so thatonly port sponson 41 will be described in detail. The starboard sponsonhas similar structure. The port sponson has a heel 50 which is forwardof heel 45. Therefore, there are three sponson heels on the boat. Theyall lie in the same plane. The boat can be taken out of the Water andset on the heels. The avoids dry-docking problems, because the boat hasa stable footing, the three heels defining a single plane of rest forthe boat, and supporting the boat.

The forward end of heel 50 meets a sharp-pointed edge 51 which extendsforwardly, and curves gently outward. Edge 51 is formed by theintersection of two curved sides 52, 53. Side 52 is inboard, and side 53is outboard. Side 52 has a more pronounced curvature than side 53, andtherefore a greater area, both in plan and in elevation than theoutboard side. Both of the sides diverge from the forward edge of thesponson to a point about midway on the respective sponsons, at whichpoint they begin to converge again toward the rear thereof. The rearface 54 of the sponson is a sloping plane which joins the rear end ofthe fantail, the two curved sides, and also a lower rear surface 58 onthe bottom of the sponson.

The heel and surface 58 are joined by a step 59, this step causing theheel to be at a lower elevation than rear surface 58. This creates ahydroplane-type step on the sponson, which aids the boat in rising outof the water when in operation.

The pronounced curvature of the inboard sides of the port and starboardsponsons, together with the curvature of the sides of the keel sponson,form two venturi channels 43, 44. The greater curvature of the inboardsurfaces of the port and starboard sponsons as compared to the curvatureof the outer surfaces, tends to create an increased pressure eifect forlifting the boat as it moves in the water.

Propulsion means 60, 61 are respectively disposed in channels 43 and 44.The propulsion means are shown as propellers 62, 63 mounted to shafts64, 65, respectively.

These shafts are supported in journals 66, 67, these journals beingformed as fins which project into said channels. The journals have ahydrofoil construction so their impedance to water flow is minimized.The propellers are preferably disposed near the rear of the channels,but they are ahead of the rear faces of the sponson and are overhung bythe fantail. The boat can then be backed into a dock without damagingthe propellers. The journals have sloping surfaces 68, 69 on theirbottom sur faces, and they are bounded by side surfaces 70, 71, and '72,73, respectively.

FIG. 6 shows journal 67, which is identical to journal 66, and whichprovides means whereby the propulsion means are mounted in the channels,and by which they are connected to driving means. To the rear surface 74of journal 67 there is fixed a bearing 75. A rubber fill 76 mayconveniently be placed in the bottom of the journal to reduce vibration.The propeller is mounted to a propeller shaft 65 that is journaled inbearing 75. The shaft passes through the rubber fill to a motor 79mounted to the hull. Because this boat has so little drag as comparedwith conventional boats, it has been found practical to drive it by theuse of high-current capacity batteries, and this is one of theadvantages attainable from the paticular boat construction. Dangers ofexplosion resulting from the use of inflammable fuels and the like canthereby be eliminated.

It will be noted that this boat is rudderless. It is controlled byoperation of the two propellers at selected speeds in selecteddirections. Other propulsion means, if used, could also be operateddiiferentially.

The entire boat, with the exception of the canopy, may be made ofconventional fiberglass-reinforced plastic construction. As one resultof its general smooth curvature, this boat is able to withstand severebuifetting which would loosen the joints of conventional boatmanufacture, without damage. Accordingly, the boat may also be madelighter in weight than conventional boats, inasmuch as it does notrequire such substantial bracing. The shape is self-bracing andsufficiently flexible to withstand heavy peak force loads.

The canopy is preferably made of a transparent material, and may be castor otherwise formed perhaps from plexiglass. In operation, thepropulsion means are started up, and the boat in moving forward tends torise up on its sponsons. The curved surface 46 on the keel sponson isthe source of the principal reaction for raising the boat initially outof the water, the port and starboard sponsons serving as stabilizers.The port and starboard sponsons soon rise on their keels as does thekeel sponson, and the step arrangement of the port and starboardsponsons tend to reduce friction by lifting a considerable proportion ofthe sponson areas out of the water in accordance with well-knownhydrodynamic concepts. It is, of course, advantageous to remove the boatas far as possible from the water during forward motion, because thiseliminates the tremendous waste of energy which is ordinarily expendedin forming a bow wave to part the water to move a boat therethrough. Itis the ability of this boat to climb up on the water, as opposed toforming a bow wave which so greatly reduces the energy requirements forpropulsion, which energy ordinarily goes into creating a bow wave.

In addition, considering other fluids through which the boat moves, thatis, the air which surrounds it as well as the water below it, anelliptical surface appears to have hydrodynamic and aerodynamicproperties which result in least waste of energy.

At any rate, whatever the theoretical reason for its ability to move atconsiderable velocities with low power requirements, this boat has beenfound to attain velocities hitherto unattainable by boats of thisgeneral class, while still requiring relatively very low horsepower forthe purpose. The boat is conveniently maneuverable by differentialoperation of the propellers, and may conveniently be docked by simplybacking the fantail against a dock. The propellers are protected by therear ends of the sponsons from damage when backing into the dock.

Any desired rearrangement may be made with the canopy. It may beeliminated entirely, if desired, but one of the advantages of theparticular construction shown is the ability to make a flat, stable boatwith considerable headroom, which may be entirely enclosed if desired.Of course, any desired portion of the canopy may be removed, or thecanopy may be removed entire- 1y. The snorkel valve, however, willprovide suitable ventilation for the boat under all operatingconditions.

This invention is not to be limited by the embodiment shown in thedrawings and described in the description which is given by way ofexample and not of limitation, but only in accordance with the scope ofthe appended claims.

I claim:

1. A boat comprising a hull having an upright central axis, a bottomhaving an outer surface, a decking having an outer surface, both of saidouter surfaces being surfaces of revolution generated by a respectiveelliptical arc revolved around said upright central axis, therebyforming a structure which is circular in plan view, a fantail integralwith said hull and projecting therefrom at the rear thereof, saidfantail being bounded in plan by a pair of tangents to the hull, whichtangents include an acute angle between them which opens toward thehull, a keel sponson integral with the bottom surface and extending inthe direction of forward motion of the boat, a port and starboardsponson integral with the bottom and projecting therefrom, one on eachside of the keel sponson, said sponsons being spaced apart so as toleave channels therebetween, propulsion means mounted in each channelfor propelling the boat, and means carried by the boat for operating thepropulsion means.

2. A boat according to claim 1 in which the port and starboard sponsonsare mirror images of each other, each having a substantially flat heelnormal to the central axis and spaced from the outer surface of thebottom, a prow edge slanting toward and intersecting said bottom surfacein a direction away from said fantail, a step adjacent said heelimmediately behind and contiguous thereto.

3. A boat according to claim 2 in which the keel sponson has a heelnormal to the central axis, a forwardly and upwardly sloping surfacecontiguous to and ahead of the heel, and a pair of curved side surfacesintersecting the sloping surface and heel.

4. A boat according to claim 3 in which the sloping surface on the keelsponson is generated by a straight line generator maintained parallel tothe transverse axis of the boat.

5. A boat according to claim 2 in which the inboard surfaces of the portand starboard sponsons are curved to form a pair of venturi sectionswith the keel section.

6. A boat according to claim 5 in which the curvature of the inboardsurfaces of the port and starboard sponsons is more pronounced than thecurvature of the outboard surfaces.

7. A boat comprising a hull having an upright central axis, a bottomhaving an outer surface, a decking having an outer surface, both saidouter surfaces being surfaces of revolution generated by a respectiveelliptical arc revolved around said central axis, a fantail integralwith said hull and projecting therefrom at the rear thereof, saidfantail being bounded in plan by a pair of tangents to the hull, whichtangents include an acute angle between them which opens toward thehull, a keel sponson integral with the bottom surface and extending inthe direction of forward motion of the boat, a port and starboardsponson integral with the bottom and projecting therefrom, one on eachside of the keel sponson, said sponsons being spaced apart so as toleave channels therebetween, the bounding surfaces of said channelsbeing curved so as to form venturi sections therebetween, propulsionmeans mounted in each channel astern of the narrowest section of saidventuri channels for propelling the boat, means carried by the boat foroperating the propulsion means, means for joining the bottom anddecking, a continuous hooked edge on each of said bottom and decking,said hooks being oppositely directed where the bottom and decking arebrought together, and a continuous collision bumper over said two hooks,and buoyant means inside the boat adjacent said joint for addingbuoyancy to the boat.

8. A boat according to claim 7 in which said propulsion means compriseshaft-driven propellers, and in which supports are provided for holdingthe propellers in their respective venturi channels.

9. A boat according to claim 8 in which the propulsion means areseparately controllable from each other.

10. A boat according to claim 8 in which the upper decking has anopening therein, and in which a canopy is provided which fits saidopening for forming an en closure.

11. A boat according to claim 10 in which the canopy is adapted to beentirely closed, and in which a snorkel valve is provided therethroughfor venting the same.

12. A boat according to claim 10 in which means are provided for joiningthe canopy to the upper decking comprising a circumferential flange onthe upper decking, a U-shaped bead fitted over said flange, the canopybeing adapted to be pressed over said bead to be retained thereby.

13. A boat according to claim 6 in which said propulsion means compriseshaft driven propellers, and in which supports are provided for holdingthe propellers in their respective venturi channels.

14. A boat according to claim 13 in which the propulsion means areseparately controllable from each other.

References Cited in the file of this patent UNITED STATES PATENTS1,832,862 Grumman Nov. 24, 1931 2,747,536 Russell May 29, 1956 2,815,730Horsdal Dec. 10, 1957 FOREIGN PATENTS 86,814 Norway Nov. 26, 1955

